This machine drives a plasma display panel.

This discussion:

https://retrocomputing.stackexchange.com/questions/13564/how-do-i-configure-a-v6366-graphics-controller-for-640x400-b-w

contains links to 

• Circuit diagrams for the machine
• PC 7640 BIOS ROM dump
• System diskette with utilities.

Having a known-good example circuit is usually better than an example from a data sheet.

There is no image of the font ROM yet.

https://archive.org/details/schneider-pc-7640 contains the Software Package and Service Manual.

https://archive.org/details/manual_PC7640_SM_SCHNEIDER_EN_DE/mode/2up is a better version the service manual. The scans are mostly lossless png, and the circuit diagrams are single pages not split into two.